Apparatus for taking a continuous x-ray picture of the dental arch

ABSTRACT

An apparatus for taking a continuous X-ray picture of the dental arch, wherein the X-ray tube and the film are moved together in such a manner that the line connecting them crosses an ellipse approximating the dental arch of each individual patient to be photographed, always making a right angle with a line tangent to the ellipse, without disturbing the relative position of the Xray tube and the film.

United States Patent 1191 Kataoka et al.

[ APPARATUS FOR TAKING A CONTINUOUS X-RAY PICTURE OF THE DENTAL ARCH [75] Inventors: Kenzo Kataoka; Yoshiaki Watanabe,

both of Kyoto, Japan [73] Assignee: Kabushiki Kaisha Morita Seisakusho, Kyoto, Japan [22] Filed: Mar. 20, 1972 21 Appl. NO.Z 236,118

Related US. Application Data [63] Continuation-impart of Ser. No. 96,889, Dec. 10,

1970, abandoned.

. 250/491 51 1111.0. G03b 41/16 581 Field Of Search...' 250/50, 61.5, 65 R, 70

[56] References Cited UNITED STATES PATENTS Huchel 250/615 Apr. 23, 1974 Faude et al. 250/615 Primary ExaminerWi1liam F1 Lindquist Y Attorney, Agent, or Firm-Christensen, OConnor, Garrison & Havelka [57 ABSTRACT An apparatus for taking a continuous X-ray picture of.

the dental arch, wherein the X-ray tube and the film are moved together in such a manner that the line connecting them crosses an ellipse approximating the dental arch of each individual patient to be photographed, always making a right angle with a line tangent to the ellipse, without disturbing the relativeposition of the Xray tube and the film.

9 Claims, 3 Drawing Figures APPARATUS FOR TAKING A CONTINUOUS X-RAY PICTURE OF THE DENTAL ARCH RELATED APPLICATION This application is a continuation-in-part of our copending application Ser. No. 96,889, filed Dec. 10, 1970, under the title APPARATUS FOR TAKING A CONTINUOUS X-RAY PICTURE OF THE DENTAL ARCH, and now abaondoned.

BACKGROUND OF THE INVENTION INCLUDING CERTAIN OBJECTS THEREOF This invention relates to an apparatus for taking x-ray pictures of the dental arch of a human being, wherein the X-ray tube and the film are moved along the dental arch of the patient so as to take necessary X-ray pictures thereof.

For dental diagnosis and treatment it is necessary to know the relation between the teeth constituting the dental arch of the patient. To this end, it is desired to,

take a continuous X-ray picture of the dental arch as a whole. For taking such a continuous X-ray picture, it is necessary to move both the X-ray tube and the film together along the dental arch of a patient without substantially disturbing the relative position of the tube and the film, and the movement must be continuous and smooth. What is more important is that the tube and the film must be moved, with the straight line connecting them always perpendicularly crossing a line tangent to the dental arch at a point thereof whose adjacent area is to be photographed. Unless the above straight line makes a right angle with the tangential line, it will become impossible to take a picture of the object at a position directly opposite thereto, and if the angle between the two lines varies as the X-ray tube and the film are movedtogether, each area of the dental arch is photographed at a different angle so that it will become of little use to have a continuous picture of the dental arch.

Accordingly, it is one object of the invention to provide an apparatus for taking a continuous X-ray picture of the dental arch, wherein the X-ray tube and the film are moved together in such a manner that the straight line connecting the tube and the'film always perpendicularly crosses a line tangent to the ellipse approximating the dental arch of the patient Without substantially disturbing the relative position of the X-ray tube and the film.

SUMMARY OF THE INVENTION The apparatus of the invention is based on the fact that the dental arch approximates an arc of a geometrical ellipse even though it more or less differs in different portions. Therefore, the arrangement is such that the X-ray tube and the film are moved together along.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be clearly understood by reading the following description of a preferred embodiment thereof with reference to the accompanying drawings,

wherein the same reference symbols in different figures denote corresponding parts, and wherein:

FIG. 1 is a somewhat schematic top plan view of the embodiment of the invention;

FIG. 2 is a view similar to FIG. 1 but showing some of the component parts in a different operative position; and

FIG. 3 is a part cut-away perspective view of one embodiment of the invention.

Referring to FIG. 1, there is shown a reference or a base 1 having a slot 2 formed therein. A pin 4 engages in the slot 2 so as to be slidable along the length thereof and is secured to one end of a link or arm 3, the other end of which is pivoted by a pin 5 to one end of a link or arm 6. In the opposite end of the arm 6 there is formed a slot 7 extending a suitable distance along the length of the arm. A pin 8 is fixed on the base 1 on a straight line with the slot 2, and at a suitable distance from one end of the slot 2. The pin 8 engages in the slot 7 formed in the arm 6 so as to be slidable along the length thereof. A pin 9 is pivotally connected at a suitable position on the arm 6, and by means to be later illustrated, pivotably supports a relatively rotatable drive member or an arm 10 having a slot 11 formed therein. The previously mentioned pin 4 slidably engages in this slot 11 as well as the slot 2. On the straight line between the slot 2 and the pin 8, and at a suitable distance from the opposite end of the slot 2, there is another pin 12 fixed to the base 1.

Along the sides of the triangle formed by the straight lines connecting the pins 8, 9 and 12, an endless flexible band 13 extends, so that as the band is driven by means to be later illustrated, the pin 9 is moved along. In practice, rotary members to be later illustrated, such as sprocket wheels, are provided on the pins 8, 9 and 12, and the band 13 takes the form of an endless chain engaged with the sprocket wheels. With such an arrangement, slip between the pin 9 and the band 13 can effectively be avoided.

An X-ray tube 21 and a film holder 22 are mounted on the opposite ends of the support arm 10, respectively. The patient is positioned intermediate the X-ray tube and the film holder in such a manner that the major axis of an ellipse approximately conforming to' pins 8 and 12 is fixed, the sum of the distance between v the pins 8 and 9, and that between the pins 9 and 12, is'constant regardless of the position of the pin 9. This means that the pin 9 is moved along the locus of the ellipse 14 with the positions of the pins 8 and 12 at its foci. As seen, the slot 2 coincides with the major axis of the ellipse 14, and in FIG. 1 the arm.10 coincides with the minor axis thereof. 7

Since the pin 8 slidably engages in the slot 7 of the arm 6, the arm 6 can move longitudinally of itself, so that even when the pin 9 is at the above-mentioned position, the arm 6 can take a desired position corresponding to the position of the pin 9. Since the pin 5 exists on the extension of a line connecting the pins 8 and I 9. Since the arm connects the pins 4 and 9, the arrangement is also such that when the pin 9 assumes a position on the minor axis of the ellipse 14, the pin 4 assumes a position at the center, that is, the intersection of the major and minor axes of the ellipse, and the arm 10 coincides with the minor axis thereof. In other words, the length of the arm 3, and the position of the 7 pin 4, are so determined that when the pin 9 assumes ever, the distance between the pins 4 and 9 changes as the pin 9 is moved. The slots 4, 7 and 11 are provided to enable smooth movement of the arms 3 and 6 in accordance with the above-mentioned distance change.

A patient is positioned between the X-ray tube 21 and the film holder 22, in such a manner that the major axis of the ellipse corresponding to the dental arch of the patient, coincides with the major axis of the ellipse 14, and the patients face is so directed that his or her dental arch is in parallel with the right-hand half of the ellipse (as viewed in FIG. 1 or 2). In other words, the patients face isso directed that X-ray is projected from behind the head. That is to say, the X-ray tube is moved transversely behind the patients head and the film, before the patients face, and as the X-ray tube is moved in the above manner, the X-ray beam is projected substantially perpendicularly to the dental arch regardless of the position of the X-ray tube. If an X-ray film is placed circumferentially on the cylindrical wall of the film holder 22, and is rotated about its own axis in synchronism with the movement of the X-ray tube, it is possible to take a continuous picture of the dental arch on the film.

Referring now to the embodiment illustrated in FIG. 3, it will be seen that the base 1 has a U-shaped or yokelike cross section, and is comprised of a pair of rounded, spaced, parallel brackets 40 and 42, interconnected by a bight connection 44 therebetween. The pin 8 extends upright between the brackets, and is fixed to both. The pin 4 is upstanding on the lower bracket 42, at a point adjacent the rounded end 42' thereof; whereas the pin 12 depends from the upper bracket 40, at a point more closely adjacent the rounded end 40' thereof. The arm 10 is slung below the lower bracket, by means of an L-shaped extension 46 upstanding thereon, the outlying end of which has the pin 9 pivotally engaged therein. The pin 9 is pivotally upstanding in the arm 6 therebelow, and connected with the pin 9, as well as with each of the pins 8 and 12, is a sprocket 48 or other such means for carrying the chain 13 interconnected among the pins. The chain 13 is driven through the pin 9, by means of a spur gear 50 thereon which is in mesh with a cooperating spur gear 52 on thelower bracket. The roller 60 is carried in a sheave block 62, and caged between the block and the vertical leg 46" of the extension is a coiled spring 64, the bias of which maintains the roller against the edge 42 of the bracket, and urges the arm 10, and the pin 9, in the direction outwardly away from the edge 42' of the bracket.

What we claim is:

1. An apparatus for taking a continuous X-ray picture of the dental arch, comprising: a base, first and second pins fixed on said base at a distance apart from each other; an elongated support member for supporting an X-ray tube and an X-ray film at the opposite ends thereof, respectively, and having a first slot formed intermediate the length thereof, a third pin fixed on said support member; a first arm pivoted to said support member by said third pin and having at one end thereof a second slot in which said first pin slidably engages; a second arm having one end pivoted to the opposite end of said first arm; a third slot formed in said base in coincidence with a straight line connecting said first and second pins; a fourth pin fixed on the opposite end of said second am and engaging in both said first and third slots; sprockets on the first, second and third pins; and a loop member endlessly passing about the sprockets and adapted to be driven so as to drive said third pin along the locus of an ellipse; said dental arch being operatively disposed intermediate said X-ray tube and film with the major axis of an ellipse approximating said dental arch coinciding with the straight line connecting said first and second pins.

2. In apparatus for recording a continuous X-ray picture of the dental arch, afixed reference, a relatively rotatable drive member which is cam connected with the reference and equipped with an X-ray source and an X-ray film holder on opposite sides of the cam connection therebetween, a relatively articulated linkage cam connected with the reference and with the drive member at the cam connection between the drive member and the reference, means forming a pivotal connection between the linkage and the drive member, and drive means operable to cause the pivotal connection between the linkage and the drive member to move through an elliptical path, and thereby cause the source and the holder to trace coaxial elliptical paths.

3. The apparatus according to claim 2 wherein the drive means includes a power unit and a system of rotary members on the reference and the pivotal connection between the linkage and the drive member, interconnected with one another and with the power unit to rotatable drive member which is cam connected with the reference and equipped with an X-ray source and an X-ray film holder on opposite sides of the cam connection therebetween, a pair of relatively articulated links, one of which is cam connected with the reference, and the othe of which is cam connected with the drive member at the cam connection between the drive member and the reference, means forming a pivotal connection between the one link and the drive mem-' her, and drive means operable to cause the pivotal connection between the one link and the drive member to move through an elliptical path, and thereby to cause the source and the holder to trace coaxial elliptical paths.

5. The apparatus according to claim 4 wherein the drive means includes a power unit on the drive member, a rotary member on the pivotal connection between the one link and the drive member, driven by the power unit, a pair of spaced rotary members on the reference, one of which is coaxial with the cam connection between the one link and the reference, and a rotary connection between the rotary member on the pivotal connection between the one link and the drive member, and each of the rotary members on the reference, whereby the rotary member on the pivotal connection between the one link and the drive member is caused to trace an elliptical path as it is driven by the power unit.

6. The apparatus according to claim 5 wherein the rotary connection takes the form of a flexible band interengaged about the respective rotary members.

7. The apparatus according to claim 6 wherein the reference has an arcuate guide thereon, and there are tion therebetween, a relatively articulated linkage cam I connected with the reference and with the drive member at the cam connection between the drivemember and the reference, means forming a pivotal connection between the linkage and the drive member, and drive means operable to cause the pivotal connection between the linkage and the drive member to move through an elliptical path, and thereby cause-the source and the holder to. trace coaxial elliptical paths.

J UN ITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0. 3 806 73 1 Dated April 23 '74 Inventor(s) Kenzo t Oka et a1 It is certified that error appears-in the' aboveddentified patent and that said Letters Patent are hereby corrected as shown below:

Claim 4, line 8, delete "othe" and insert therefor -other-;

line 14, delete-"to cause" and substitute therefor -cause-.

Claim 8, line 2, delete "taken" and insert therefor take-.

Signed and sealed this 24th day of September 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. 6. VARSHALL DANN Attesting Officer Commissioner of Patents 

1. An apparatus for taking a continuous X-ray picture of the dental arch, comprising: a base, first and second pins fixed on said base at a distance apart from each other; an elongated support member for supporting an X-ray tube and an X-ray film at the opposite ends thereof, respectively, and having a first slot formed intermediate the length thereof, a third pin fixed on said support member; a first arm pivoted to said support member by said third pin and havIng at one end thereof a second slot in which said first pin slidably engages; a second arm having one end pivoted to the opposite end of said first arm; a third slot formed in said base in coincidence with a straight line connecting said first and second pins; a fourth pin fixed on the opposite end of said second arm and engaging in both said first and third slots; sprockets on the first, second and third pins; and a loop member endlessly passing about the sprockets and adapted to be driven so as to drive said third pin along the locus of an ellipse; said dental arch being operatively disposed intermediate said X-ray tube and film with the major axis of an ellipse approximating said dental arch coinciding with the straight line connecting said first and second pins.
 2. In apparatus for recording a continuous X-ray picture of the dental arch, a fixed reference, a relatively rotatable drive member which is cam connected with the reference and equipped with an X-ray source and an X-ray film holder on opposite sides of the cam connection therebetween, a relatively articulated linkage cam connected with the reference and with the drive member at the cam connection between the drive member and the reference, means forming a pivotal connection between the linkage and the drive member, and drive means operable to cause the pivotal connection between the linkage and the drive member to move through an elliptical path, and thereby cause the source and the holder to trace coaxial elliptical paths.
 3. The apparatus according to claim 2 wherein the drive means includes a power unit and a system of rotary members on the reference and the pivotal connection between the linkage and the drive member, interconnected with one another and with the power unit to be driven in unison by the unit.
 4. In apparatus for recording a continuous X-ray picture of the dental arch, a fixed reference, a relatively rotatable drive member which is cam connected with the reference and equipped with an X-ray source and an X-ray film holder on opposite sides of the cam connection therebetween, a pair of relatively articulated links, one of which is cam connected with the reference, and the othe of which is cam connected with the drive member at the cam connection between the drive member and the reference, means forming a pivotal connection between the one link and the drive member, and drive means operable to cause the pivotal connection between the one link and the drive member to move through an elliptical path, and thereby to cause the source and the holder to trace coaxial elliptical paths.
 5. The apparatus according to claim 4 wherein the drive means includes a power unit on the drive member, a rotary member on the pivotal connection between the one link and the drive member, driven by the power unit, a pair of spaced rotary members on the reference, one of which is coaxial with the cam connection between the one link and the reference, and a rotary connection between the rotary member on the pivotal connection between the one link and the drive member, and each of the rotary members on the reference, whereby the rotary member on the pivotal connection between the one link and the drive member is caused to trace an elliptical path as it is driven by the power unit.
 6. The apparatus according to claim 5 wherein the rotary connection takes the form of a flexible band interengaged about the respective rotary members.
 7. The apparatus according to claim 6 wherein the reference has an arcuate guide thereon, and there are yieldable biasing means interposed between the guide and the drive member to maintain tension in the band.
 8. The apparatus according to claim 4 wherein the cam connections taken the form of pin and slot connections.
 9. In combination, a fixed reference, a relatively rotatable drive member which is cam connected with the reference and equipped with an X-ray source and an X-ray film holder on opposite sides of the cam connection therebetween, a relatively Articulated linkage cam connected with the reference and with the drive member at the cam connection between the drive member and the reference, means forming a pivotal connection between the linkage and the drive member, and drive means operable to cause the pivotal connection between the linkage and the drive member to move through an elliptical path, and thereby cause the source and the holder to trace coaxial elliptical paths. 